Data center power conversion efficiency management

ABSTRACT

A data center energy management (DCEM) server configures a power supply in the data center. The DCEM server sums input alternating current (AC) power of the power supply to a total AC power of the data center, wherein the total AC power of the data center is a sum of AC power of a plurality of power supplies. The DCEM server sums output direct current (DC) power of the power supply to a total DC power of the data center and reports a ratio of total AC power to total DC power as data center power conversion efficiency. The DCEM server sets a preset power supply efficiency threshold. The DCEM server determines that a real-time power efficiency level is below the power supply efficiency threshold. The DCEM server, responsive to a determination that real-time power efficiency level is below the power supply efficiency threshold, may remedy the power supply.

This application claims benefit of priority of patent application Ser.No. 12/878,063 (Attorney Docket number AUS920100267US1), filed on Sep.9, 2010, which is herein incorporated by reference.

BACKGROUND

The present invention relates generally to a computer implementedmethod, data processing system, and computer program product formonitoring, measurement, and management of the efficiency of electricalpower delivery systems. More specifically, the present invention relatesto detecting degradation in power supplies in a data center andproactively removing degraded power supplies from service or otherwisemodifying power delivery or system loads to enhance productive use ofelectricity.

There are over 1.5 billion power supplies used to convert alternatingcurrent (AC) into direct current (DC) useful for devices such astelevisions, cellular phones, and computers. Approximately 11% ofelectricity in the U.S. flows through power supplies. Most powersupplies are between 20-90% efficient in converting AC to DC. Inaddition to wasting electricity, an inefficient power supply can produceunwanted heat. In a data center with a high density of informationtechnology (IT) equipment, removing this extra heat results inadditional cost on top of the increased IT electricity consumption dueto power conversion inefficiency.

Many factors may impact efficiency of power supplies. Contamination andcomponent wear can reduce efficiency during the life of a power supply.In addition, dust and humidity may clog a power supply's cooling fans.Dust collected on the power supply's heat sink surface reduces itsefficiency in removing heat. This gradual deterioration in the powersupply's fan and heat sink performance results in raising thetemperature of the power supply, which leads to reducing the powersupply efficiency. In addition, surges and voltage variations in the ACarriving from the mains (i.e. the chief power lines entering a datacenter) also limit the efficiency of a power supply. All these reasonsadd uncertainty to the actual run-time power supply efficiency.Eventually, degradation of a power supply can lead to its failure anddisruption of the IT equipment operation. Without monitoring the actualpower supply efficiency at run time, there is no way to detect itsefficiency deterioration, predict failure, or, in some cases, evendiscover its failure.

Accordingly, a remedy to the situation is warranted.

BRIEF SUMMARY

The present invention provides a computer implemented method, dataprocessing system and computer program product for managing a pluralityof power supplies in a data center. A data center energy management(DCEM) server configures a power supply in the data center. The DCEMserver sums input alternating current (AC) power of the power supply toa total AC power of the data center, wherein the total AC power of thedata center is a sum of input AC power of a plurality of power supplies.The DCEM server sums output direct current (DC) power of the powersupply to a total DC power of the data center and reports a ratio oftotal AC power to total DC power as data center power conversionefficiency (DCPCE). The DCEM server sets a preset power supplyefficiency threshold. The DCEM server determines that a real-time powerefficiency level is below the power supply efficiency threshold. TheDCEM server, responsive to a determination that real-time powerefficiency level is below the power supply efficiency threshold, mayremedy the power supply. Remedy of the low efficiency power supplies inthe data center improves the DCPCE, and hence reduces wasted energy inpower supplies, and improves the overall data center energy efficiency.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, as well asa preferred mode of use, further objectives and advantages thereof, willbest be understood by reference to the following detailed description ofan illustrative embodiment when read in conjunction with theaccompanying drawings, wherein:

FIG. 1A is a block diagram of a data processing system in accordancewith an illustrative embodiment of the invention;

FIG. 1B is a block diagram of a power supply unit (PSU) in accordancewith an illustrative embodiment of the invention;

FIG. 1C is a block diagram of a software component called the energymanagement supervisor (EMS) in accordance with an illustrativeembodiment of the invention;

FIG. 2A is a first configuration of the EMS in accordance with anillustrative embodiment of the invention;

FIG. 2B is an alternative configuration of the EMS in accordance with anillustrative embodiment of the invention;

FIG. 2C is an alternative configuration of the EMS in accordance with anillustrative embodiment of the invention;

FIG. 2D is an alternative configuration of the EMS in accordance with anillustrative embodiment of the invention;

FIG. 3A is an initial configuration for alarm level and warning level inaccordance with an illustrative embodiment of the invention;

FIG. 3B is a table or matrix of matrix cells in accordance with anillustrative embodiment of the invention;

FIG. 4 is a flowchart of data center energy management (DCEM) serverprocess in accordance with an illustrative embodiment of the invention;

FIG. 5 is a dashboard to present a data center power conversionefficiency in accordance with an illustrative embodiment of theinvention;

FIG. 6 is a flowchart of a PSU embodiment in accordance with anillustrative embodiment of the invention;

FIG. 7 is a flowchart of a PSU embodiment in accordance with analternative illustrative embodiment of the invention; and

FIG. 8 is a flowchart of an alternative process to transmit anomaliesconcerning power related metrics in accordance with an illustrativeembodiment of the invention.

DETAILED DESCRIPTION

With reference now to the figures and in particular with reference toFIG. 1A, a block diagram of a data processing system is shown in whichaspects of an illustrative embodiment may be implemented. Dataprocessing system 100 is an example of a computer, in which code orinstructions implementing the processes of the present invention may belocated. In the depicted example, data processing system 100 employs ahub architecture including a north bridge and memory controller hub(NB/MCH) 102 and a south bridge and input/output (I/O) controller hub(SB/ICH) 104. Processor 106, main memory 108, and graphics processor 110connect to north bridge and memory controller hub 102. Graphicsprocessor 110 may connect to the NB/MCH through an accelerated graphicsport (AGP), for example.

In the depicted example, local area network (LAN) adapter 112 connectsto south bridge and I/O controller hub 104 and audio adapter 116,keyboard and mouse adapter 120, modem 122, read only memory (ROM) 124,hard disk drive (HDD) 126, CD-ROM drive 130, universal serial bus (USB)ports and other communications ports 132, and PCl/PCIe devices 134connect to south bridge and I/O controller hub 104 through bus 138 andbus 140. PCl/PCIe devices may include, for example, Ethernet adapters,add-in cards, and PC cards for notebook computers. PCI uses a card buscontroller, while PCIe does not. ROM 124 may be, for example, a flashbinary input/output system (BIOS). Hard disk drive 126 and CD-ROM drive130 may use, for example, an integrated drive electronics (IDE) orserial advanced technology attachment (SATA) interface. A super I/O(SIO) device 136 may be connected to south bridge and I/O controller hub104.

An operating system runs on processor 106 to coordinate and providecontrol of various components within data processing system 100 in FIG.1A. The operating system may be a commercially available operatingsystem such as Microsoft® Windows® XP. Microsoft and Windows aretrademarks of Microsoft Corporation in the United States, othercountries, or both. An object oriented programming system, such as theJava™ programming system, may run in conjunction with the operatingsystem and provides calls to the operating system from Java™ programs orapplications executing on data processing system 100. Java™ is atrademark of Sun Microsystems, Inc. in the United States, othercountries, or both.

Instructions for the operating system, the object-oriented programmingsystem, and applications or programs are located on storage devices,such as hard disk drive 126, and may be loaded into main memory 108 forexecution by processor 106. The processes of the present invention canbe performed by processor 106 using computer implemented instructions,which may be located in a memory such as, main memory 108, read onlymemory 124, or in one or more peripheral devices.

Those of ordinary skill in the art will appreciate that the hardware inFIG. 1A may vary depending on the implementation. Other internalhardware or peripheral devices, such as flash memory, equivalentnon-volatile memory, and the like, may be used in addition to, or inplace of, the hardware depicted in FIG. 1A. In addition, the processesof the illustrative embodiments may be applied to a multiprocessor dataprocessing system.

In some illustrative examples, data processing system 100 may be apersonal digital assistant (PDA), which is configured with flash memoryto provide non-volatile memory for storing operating system files and/oruser-generated data. A bus system may be comprised of one or more buses,such as a system bus, an I/O bus, and a PCI bus. Of course, the bussystem may be implemented using any type of communications fabric orarchitecture that provides for a transfer of data between differentcomponents or devices attached to the fabric or architecture. Acommunication unit may include one or more devices used to transmit andreceive data, such as a modem or a network adapter. A memory may be, forexample, main memory 108 or a cache such as found in north bridge andmemory controller hub 102. A processing unit may include one or moreprocessors or CPUs. The depicted example in FIG. 1A is not meant toimply architectural limitations. For example, data processing system 100also may be a tablet computer, laptop computer, or telephone device inaddition to taking the form of a PDA.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an”, and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method, or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.), or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablestorage devices(s) having computer readable program code embodiedthereon.

Any combination of one or more computer readable storage device(s) maybe utilized. A computer readable storage device may be, for example, butnot limited to, an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system, apparatus, or device, or any suitablecombination of the foregoing. More specific examples (a non-exhaustivelist) of the computer readable storage device would include thefollowing: a portable computer diskette, a hard disk, a random accessmemory (RAM), a read-only memory (ROM), an erasable programmableread-only memory (EPROM or Flash memory), a portable compact discread-only memory (CD-ROM), an optical storage device, a magnetic storagedevice, or any suitable combination of the foregoing. In the context ofthis document, a computer readable storage device may be any tangibledevice that can store a program for use by or in connection with aninstruction execution system, apparatus, or device. The term“computer-readable storage device” does not encompass a signalpropagation media such as a copper cable, optical fiber or wirelesstransmission media.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like, and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer, or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable storage device that can direct a computer, other programmabledata processing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablestorage device produce an article of manufacture including instructionswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto amicrocontroller, a service processor, or other programmable dataprocessing apparatus, or other devices to cause a series of operationalsteps to be performed on the computer, other programmable apparatus orother devices to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide processes for implementing the functions/actsspecified in the flowchart and/or block diagram block or blocks.

As the power supply unit (PSU) power conversion efficiency deterioratesover time because of aging and environmental parameters (for examplehumidity, contamination particles, and temperature), PSU efficiency canbe monitored over time. Upstream devices may collect information fromthe PSUs, such as input power and output power of one or more PSUs.Monitoring the power supply efficiency of an individual PSU, isperformed by an energy management supervisor (EMS). The EMS monitorsindividual power supplies, or a small number of power supplies, plus thepower supplies input, generally AC or DC, and output powers. Bymonitoring the PSU, the EMS calculates the power supply efficiency,detects efficiency degradation below a certain threshold, and detectspower supply failure. The EMS communicates with a data center energymanagement (DCEM) server to give power supply efficiency and AC/DC powernumbers reports, and receive configuration commands (for example thethreshold levels), plus report alarms and errors. An EMS providesmonitoring and reporting of PSU functionality. Various embodiments,below, show how the EMS may be functionality placed in a power supplypowered device, a power supply unit, an intelligent power distributionunit, and the like, and thereby collect power related metrics and insome cases report PSU power related metrics and operational status tothe DCEM server.

In a data center, where thousands of IT units are each fed by power fromone or more PSUs, DCEM server software communicates with EMSs to keeptrack of the PSU efficiencies, and performs management tasks thatimprove the overall energy efficiency of the data center.

The illustrative embodiments permit a data center operator to migrateworkloads in response to non-optimal shifts in operation of one or morepower supplies of the data center. In addition, where a power supplyoperates at a power supply efficiency that suggests the power supply isfailing or otherwise beyond an alarm threshold, embodiments may allowautomatic ordering of inspections and/or maintenance for affected powersupplies. Accordingly, the data processing system, or variations of it,may be configured to operate as a DCEM server, an intelligent powerdistribution unit (iPDU) controller, an IT equipment service processor,and/or power supply controller in a coordinated fashion.

The DCEM server may sum input AC power of power supplies to a total datacenter AC power. The total data center AC power is a sum of average ACpower of each of a plurality of power supplies over a specific period.The average value of the power supply input AC power can be determinedby sampling power supply input AC power over a period of time. The DCEMserver sums output DC power of the power supply to a total DC power ofthe data center. The average value of the power supply input DC powercan be determined by sampling power supply input DC power over a periodof time. The DCEM server calculates a ratio of total AC power to totalAC power to form data center power conversion efficiency. FIG. 4explains this operation fully below.

The DCEM server can set an alarm level for each of the plurality ofpower supplies, wherein the alarm level is a power supply efficiency(PSE) threshold. The DCEM server sends PSE thresholds to the EMS ofcorresponding power supplies. The EMS may determine, on a scheduledbasis, whether a real-time power efficiency level is below the powersupply efficiency threshold. The PSE threshold may be based on oneselected from the group consisting of temperature and loading.Temperature can be, for example, ambient temperature, which is thetemperature of the air in a representative location near or inside thepower supply. PSU loading can be a percentage of measured output powerthat IT devices are consuming from the output power rating of the PSU.The DCEM server, responsive to a determination that the real-time powerefficiency level is below the PSE threshold, may remedy the power supplylevel. The remedy may occur in several different ways, including, forexample, issuing maintenance request, issuing an inspection request,migrating workloads to backup power supplies, etc.

FIG. 1B is a block diagram of a power supply unit (PSU) in accordancewith an illustrative embodiment of the invention. Power supplies or PSUsare modules that convert AC power to DC power used by IT equipment, forexample, data processing server, storage, and network system components.A PSU can regulate the signal to provide a stable DC signal at itsoutputs. Some power supplies incorporate batteries to provideuninterrupted power supply; such a power supplier is called anuninterruptible power supply (UPS).

Power supply unit (PSU) 157 receives AC (or DC) input 151 as, forexample, a sinusoidal wave that is described by current, I_(in), and avoltage, V_(in). The root mean square (rms) value of the voltage andcurrent AC's waveform (V_(rms) and I_(rms)) are used to calculate thepower consumption from an AC power line. For a DC voltage signal, therms values of voltage and current signals are equal to the correspondingDC values. The average AC input power P_(in) for the AC of PSU 157 iscalculated as the product of apparent power (V_(rms)×I_(rms)), and apower factor. The power factor is a positive value between 0 and 1,depending on the phase angle between current and voltage signals. Theinput phase angle (Φ) is defined as the difference between the phases ofthe PSU input current waveform and the PSU input voltage waveform. Forsinusoidal voltage and current waves, the power factor is calculated ascos(Φ), and the real power is equal to I_(rms)×V_(rms)×cos(Φ). Forsimplicity, in the rest of this document, real power will be referred toas ‘AC power’ or ‘power’. For a pure resistive load, the power factorequals 1. In general, power factor is a fraction less than 1.

The PSU 157 provides a number, ‘n’, of DC outputs, each having acorresponding voltage value (V_(n)). Each of the IT equipment in a datacenter is supplied by DC power from one or more PSUs by means of two ormore conductors connecting the output of PSU to IT equipment's powerinput pins. The supply current drawn from each of these outputs (I_(n))depends on the load supplied by that output, which in general variesover time, based on the IT equipment's workload. A first DC output hascurrent-voltage pair, I₁, V₁, respectively. A second DC output can havea current-voltage pair, I₂, V₂, respectively. A final DC output can havea current-voltage pair, I_(n), V_(n), respectively. A PSU may sum the DCpower based on such current-voltage pairs to calculate a total output DCpower of the power supply. The output power of a PSU with DC output iscalculated as the product of I_(i) and V_(i).

PSU 157 may rely on an on-board microcontroller to perform the power andefficiency calculations, and report such calculations to a DCEM serverusing, for example, Ethernet, wireless, power line communications, orother communications means. The on-board microcontroller may run aninstance of an energy management supervisor (EMS).

FIG. 1C is a block diagram of an energy management supervisor (EMS), inaccordance with an illustrative embodiment of the invention. An EMS is asoftware component that operates using the resources of a dataprocessing system, which can be configured, for example, using a subsetof components of a data processing system of FIG. 1A. EMS 210 monitors asingle PSU or a small number of PSUs, to obtain input and output voltageand current measurements. The EMS may calculate power consumption andoverall power supply efficiency. An EMS can be embedded in a monitoredPSU, in an iPDU, or in IT equipment supplied by the PSU power. FIGS. 2A,2B, 2C, and 2D present these different EMS embodiments.

Accordingly, EMS 210 is logically presented as relying on data inputs,I_(in), V_(in), I₁, V₁, I₂, V₂, . . . , I_(n), and V_(n), representingcurrent and voltage measurements of corresponding power supply input andoutput parameters. Such values may be transported via network 215. It isappreciated that the EMS may perform its task in any unit wherecomputing resources are available and to which currents and voltages arereported, either in analog or digital signals. Accordingly, the EMS canbe resident within, for example, a PSU (e.g. FIG. 2A), a DC powered ITequipment, or an intelligent power distribution unit (iPDU).

An iPDU is a kind of power strip that includes an additional capabilityof communicating with IT equipment about current flowing through theiPDU. The iPDU can be rack-mounted, and more than one iPDU can bemounted in one rack. It takes as an input the AC power feeding the rackand distributes the AC to a plurality of outputs. Each output carries ACcurrent to IT equipment mounted in the same rack. The iPDUs containversatile sensors that provide power consumption information of theattached devices, and may also sense environmental information such astemperature and humidity. The iPDU's serial and LAN interfaces allow forremote monitoring and management through networked data processingsystems. Networked data processing systems may be, for example, thosethat are executing a Web browser, any SNMP based Network ManagementSystem, Telnet, or a console.

FIG. 2A is a first configuration 202 of the EMS in accordance with anillustrative embodiment of the invention. EMS 210 resides within PSU 207to communicate with network 215, such as the EMS and network 215 of FIG.1C. PSU 207 provides DC to DC powered device 211, which in turn,provides PSU input current, output current and voltage measurements toEMS 210. A DC powered device performs an information technologyfunction. An information technology function can be storing or otherwiseaccessing data in non-volatile storage, communicating informationaccording to a networking protocol, processing information in at leastone processor core, and the like. Information technology equipment isequipment that is configured to perform at least one informationtechnology function. The PSU, as configured in first configuration 202may perform processes described in flowcharts described in FIGS. 6 and7.

FIG. 2B is an alternative configuration 212 of the EMS in accordancewith an illustrative embodiment of the invention. PSU 207 provides DC toDC powered device 211, which in turn, provides PSU input current, outputcurrent and voltage measurements to EMS 210. The EMS can measure the PSUoutput current and voltage measurements directly. However, in this case,the PSU input parameters are passed by the PSU to the EMS. EMS 210reports PSU measurement and efficiency data via network 215 to the DCEMserver 251.

IT equipment can be powered by more than one PSU in a redundant fashionfor fault tolerance. If one or more redundant PSUs fails, then the ITequipment can continue to draw its current from another functioning PSU.

FIG. 2C is an alternative configuration 232 of the EMS in accordancewith an illustrative embodiment of the invention with redundant powersupply. PSUs 207 and 208 each provide DC power in a redundant fashion toDC powered device 211. EMS resides within DC powered device 211, andmonitors all the PSUs feeding it simultaneously. EMS 210 reports itsPSUs measurement and efficiency data via network 215 to DCEM server 251.

FIG. 2D is an alternative configuration 242 of the EMS in accordancewith an illustrative embodiment of the invention. Data center level ACpower is distributed to different racks inside the data center. Insideeach rack, AC power 250 is distributed to rack mounted IT equipment byintelligent power distribution unit (iPDU) 255 feeding this equipment.Equipment can be fed by more than one iPDU. In this embodiment, iPDU 255distributes AC to PSUs 206, 207, 208, and 209, which in turn provide DCpower in a redundant fashion to DC powered devices 211 and 213. An iPDUcan measure the AC current and voltage values consumed by each of thePSUs connected to it. Each PSU provides power to DC powered devices, andsignals to the iPDU information concerning each DC power output. EMS210, within iPDU 255, collects this information and provides it vianetwork 215 to DCEM server 251. The iPDU information can be based oncurrent (I) and voltage (V) signals collected from the PSUs connected toit. In this example the iPDU information can be a power supplyefficiency, calculated from the AC power consumed by each PSU and the Iand V signals at each corresponding PSU output. In addition, a clientconsole 259 may operate to provide a user interface for control of DCEMserver 251 as well as report current conditions of the data center. DCEMserver 251 and client console 259 may be, for example, data processingsystem 100 of FIG. 1A.

An EMS, DCEM server or both may be configured to take action when apower supply degrades in performance, for example, in response to aging,environmental conditions, or electro-mechanical faults. Actions can betaken in response to power efficiency descending below levels orthresholds previously set. For example, An EMS can be configured to turnoff a PSU with a degraded efficiency to prevent further deterioration,send an alarm to the DCEM server, or set a visual or audible alarm thatcorresponds to the severity of the alarm. The DCEM server can issue amaintenance or inspection order for the deteriorating PSU, a purchaseorder for a replacement PSU, and/or a workload migration command ofworkload running on the IT equipment powered by a failing PSU.

FIG. 3A is an initial configuration for alarm level and warning level inaccordance with an illustrative embodiment of the invention. Powersupply efficiency is the ratio of the power arriving at an input to thepower supply divided by the sum of all power at the outputs of the powersupply. Accordingly, such a power supply efficiency can be representedas a percentage. A power supply efficiency threshold is a preset valuethat may be used as a basis for taking action when the power supplyefficiency of a PSU descends below the threshold.

PSE thresholds may be, for example, a warning level, or an alarm level.A warning level is a threshold for a power supply, which may be specificto a temperature and power loading. When the PSU efficiency falls belowthese thresholds, a benefit accrues by acting to remedy the drop ofefficiency, thereby reducing the wasted power conversion losses. Analarm level is a threshold for a power supply, which may be specific toa temperature and/or loading, that when penetrated below indicates a PSEthat indicates assured benefits will result from changing/remedying theconfiguration. A warning level is a level of power supply efficiencyhigher or better than the alarm level.

The alarm level may be a preset power supply efficiency threshold. Apreset power supply efficiency threshold may be a threshold set by amanufacturer, determined initially by testing newly installed PSUs, orprovided by a system administrator of a data processing center.

A lower bound of the PSE can be minimum efficiency 301, which can be,for example, 0%, where the output power delivered to IT equipment iszero watts. An upper bound of the PSE can be maximum efficiency 349,which can be, for example, 100%, where the PSU output power is equal tothe PSU input power, with no power loss. Status of a given power supplycan be divided into three corresponding colors of red, yellow, andgreen, depending on what the current range is for the power supplyefficiency.

Power supply efficiencies above PSE warning level 310 can be consideredto be nominal, or green. Power supply efficiencies below PSE warninglevel 310 and above PSE alarm level 315 can be considered elevated, oryellow. Power supply efficiencies below PSE alarm level 315 can beconsidered critical, or red. A warning level can be uniformly set forall PSUs to match a goal set for the data center, in which they arelocated. Such a goal can be an system operator's preferred target foroperating the data center. Accordingly, as explained below, an averagePSE level of all PSUs in the data center falls below the goal the DCEMmay show that the data center, as a whole, is not attaining the goal.

Alternatively, a more elaborate system of establishing thresholds orvalid ranges may be used. One in which each PSU is assigned a table ormatrix of thresholds or ranges that correspond to alarm and warninglevels. In other words, the PSE alarm levels and PSE warning levels maybe looked up from tables, as well as a from target data center powerconversion efficiency (DCPCE). In one embodiment, these tables can bepopulated by the PSU manufacturer, based on the specific PSU designparameters, and PSU performance under different environmental andloading conditions. A warning level may be considered as a lower boundon the efficiency level of a PSU, below which a PSU is considered tohave poor performance due to aging, for example. An alarm level may beconsidered as the manufacturer's indication of an abnormality of thePSU, which mandates a PSU maintenance or replacement by the maintenancetechnician. In another embodiment, these tables can be programmableafter PSU installation in a data center to arbitrary values asillustrated in embodiments below.

FIG. 3B is a table or matrix of cells in accordance with an illustrativeembodiment of the invention. The matrix may store three values percombined temperature and loading ranges. Each such value may be athreshold, for example, for power supply efficiency. Load or loading isthe proportion of the power supply's rated power that is being deliveredto its outputs. Each matrix cell provides a target power efficiency, aPSE warning level and/or a PSE alarm level for a distinct range oftemperature and loadings. An operator selected operational range is arange that relies on a value of the matrix as a lower or upper limit.For example, an operator selected operational range can be any powersupply efficiency at or above 80%, in the case of matrix cell 343.

Matrix cells 340 are the warning levels for ranges of loading attemperatures above 80° F. Matrix cells 350 are the warning levels forranges of loading at temperatures above 100° F.

Matrix cells 360 are the alarm levels for ranges of loading attemperatures above 80° F. Matrix cells 370 are the alarm levels forranges of loading at temperatures above 100° F. Accordingly, by usingmultidimensional tables, a corresponding alarm level can be looked upfor each combination of loading and temperature. Similarly, acorresponding alarm level can be added, either by the manufacturer, orthe purchaser, such that an alarm level is set for each combination ofloading and temperature.

FIG. 4 is a flowchart of data center energy management (DCEM) serverprocess in accordance with an illustrative embodiment of the invention.One or more steps may be implemented dependent on an EMS action or bydelegating processing of substeps to an EMS. A data center is the dataprocessing systems and support systems at a geographic location. A dataprocessing center can be built from, for example, a plurality of dataprocessing systems 100 of FIG. 1A. Support systems may be, for example,network, storage, power, and cooling equipment.

Initially, in monitoring process 400, a DCEM server may set data centerpower conversion efficiency targets (step 401). The setting may be basedon a user interaction via a terminal to fill values of matrix cells 320and matrix cells 330, of FIG. 3B. The targets may include a DCPCE, whichmay establish an overall power conversion efficiency for all powersupplies in the data center. Next, the DCEM server may set PSEthresholds (step 403). The PSE thresholds can be alarm levels andwarning levels recorded to matrix cells 340, 350, 360, and 370. Step 403may be performed iteratively for all power supplies in the data center.In addition, the thresholds can be based on specifications of the PSUaccording to its manufacturer. Accordingly, the DCEM server mayconfigure power supplies in the data center by setting thresholds andother values within matrix cells.

A threshold is a one or more fixed values that are used to measure arelationship to one or more performance values of a PSU. Examples oftypes of fixed values can include, a temperature, a loading, a current,a voltage and a power supply efficiency for a power supply unit.Accordingly, a threshold for PSE can be coupled to a specific range oftemperature or to a specific range of loading. As such, the PSEthreshold applicable to a PSU is multidimensional. Many forms of tablescan be created that create thresholds under different conditions. Forexample, a table of thresholds can be created for different ranges ofoutput power, where a threshold is used to check whether input power isbelow a threshold looked-up on the basis of, for example, temperature,loading and input power. Furthermore, the input power can be a sum ofthe products of all input currents and input voltages. Accordingly, athreshold can be based on input currents, input voltages, outputcurrents, and output voltages. Moreover, a threshold can be expressed interms of power supply efficiency, current, and voltage.

Step 403 can include a phase where a PSU is operated at varyingtemperatures and loading, for example, shortly after PSU installation.During its initial power on, a PSU can measure, during a self testperiod, its own initial power supply efficiencies. The PSU determinesthe power supply levels by calculating a power supply efficiency. Apower supply efficiency can be a power supply efficiency determined fora value of a variable load. A variable load is one or more circuits thatdraw power from a DC output of a power supply which may be turned on oroff in order to change the power consumed. Variable loads can be asimple resistive load, a resistance-capacitance circuit load, or ageneral resistance-capacitance-inductance load. Alternatively,multi-core processors may be placed in-whole or in-part in a powersaving mode to test the PSU under different load conditions. Forexample, the power supply efficiency can be based on a measured inputcurrent or an output current or an input voltage. A self test period isthe time when a PSU is tested in varying configuration of, for example,loads placed on the PSU. In a different embodiment, a PSU can populatethese tables with actual efficiencies during the self test period, basedon actual environment and loading values. A loading value is a specificload placed on a power supply output. The loading value can be apercentage of a rated load for a power supply. A power supply output isany to which output the PSU delivers direct current.

Once the initial power supply efficiencies are determined, the PSU mayestablish operator-selected margin factors. Desired margin factors arethresholds or fractions of an initially determined operationalcapability, set to define either safe or energy efficient operationranges. The desired margin factor can be defined by a range between apair of thresholds, for examples, the PSU input voltage and the PSUoutput voltages. If the PSU measured input voltage is higher than themaximum PSU input voltage, an input overvoltage alarm message will besent. The desired margin factor can alternatively be defined by a singlethreshold, for example, the phase angle between input current and inputvoltage (φ), and the input and output currents. If one PSU outputcurrent drawn from the power supply is larger than the maximum outputcurrent threshold, a PSU output over-current alarm message will be sentby the EMS. Another example is the calculated power supply efficiency,as determined during the self test period. If the PSU measuredefficiency falls below the PSU efficiency threshold, a low efficiencyPSU warning message may be sent by the EMS. Multiple desired operationfactors can be configured for one parameter. For example, a warninglevel and an alarm level can be configured to trigger PSU efficiencydeterioration levels at different levels of severity, as shown in FIG.3A.

In a third embodiment, these tables can be populated at manufacturingtime, and serve as a baseline for future reference. In other words, thevalues for a PSU can be stored to, for example, ROM, flash memory andthe like, and be uploaded to a DCEM server promptly after initial use ofthe PSU in the data center. Accordingly, a temperature and a loadingrepresentative of the range of values to which a matrix cell correspondsmay be tested, and the result used as a basis for setting a matrix cell.For example, a newly installed PSU can be determined to have a powersupply efficiency of 84% when the temperature is 85° F. and loaded at aloading value of 60%. This power supply efficiency can be offset by, forexample, 4% to provide a warning level, for example, of 80%, in matrixcell 343 of matrix 340 in FIG. 3B. Alternatively, a power supplyefficiency threshold, establishing a warning level, can be set byapplying a desired margin factor to the power supply efficiencydetermined during self test period. For example, a desired margin factorcan be 95.2%. Accordingly, the warning level established for a powersupply efficiency of 84% can be 84%×95.2%=80%. For example, a desiredmargin factor may be a factor used to multiply a power supplyefficiency, as set at self test period, in order to obtain a resultantwarning or error threshold.

Next, the DCEM server may obtain power related metrics for each powersupply on an iterative basis (step 405). A power related metric is avalue that may be measured or calculated with respect to a power supplyunit concerning current. A power related metric may be, for example,input current (I_(in)), output current (I_(out)), input voltage(V_(in)), output voltage (V_(out)), input power, output power, phaseangles of the AC, or power supply efficiency. Each such power relatedmetric may have a corresponding operator-selected operational range.Among the power related metrics, the DCEM server may obtain, forexample, power supply efficiencies (PSE) for each power supply at step405. Step 405 may iterate over the entire set of power supplies in thedata center. Alternatively, step 405 may allow the DCEM server toiterate over a subset of the data center power supplies, namely, thoseplaced in a low efficiency power supply unit (PSU) list, explainedbelow. First, the DCEM server may request an EMS to calculate areal-time input AC power of a PSU. Second, the DCEM server may requestan EMS to calculate a sum of all output DC powers at the PSU outputs.Third, the DCEM server may request the EMS to calculate the PSUefficiency, and the EMS may compute the real-time power efficiency level(PSE) as the ratio of the sum of output DC powers divided by thereal-time input AC power. Finally, the EMS may obtain temperature andloading information for the PSU, for example, based on sensors placed inor near the PSU. Thus, the EMS may look up the warning and alarm levelsthat correspond to run-time temperature and loading values, and forwardthem to the DCEM along with the run time PSU efficiency.

Alternatively, the average values of all these parameters can be trackedby the EMS over a period of time, as specified by the DCEM server.Accordingly, a single value for each parameter over the period can besent back to the DCEM server, rather than an instantaneous value at thetime this information is requested.

Next, the DCEM may determine for each power supply, whether a powerrelated metric is outside of a range, or otherwise exceeds a threshold.For example, the DCEM may determine whether the PSE level (real-time oraveraged) is below a corresponding alarm level of the power supply (step407). Such a determination may be based on the temperature and loadingof the power supply. Alternatively, this determination is done by theDCEM server, based on the loading, environmental, and loadinginformation collected for each PSU.

Each determination involves the DCEM server and/or EMS performing anumber of substeps.

A positive determination at step 407 may cause the DCEM server to takeremedial action. In other words, responsive to a determination that thereal-time power efficiency level is below the PSE threshold, the DCEMserver may remedy the power supply. For example, the DCEM server mayissue a maintenance request or purchase order request (step 409) as aform of remedy. The maintenance request may result in a purchase orderrequest for a replacement power supply. A replacement power supply is apower supply that provides at least as much DC power output as the powersupply compared at step 407 and found to be underperforming. Next, ifthe PSU inspected in step 407 has a redundant backup PSU, the DCEMserver and/or the EMS may determine whether the backup PSU is able tohandle a load of the power supply (step 411). The backup power supply isan alternative power supply that can supply power to a data processingsystem having sufficient resources to execute the processes and/orapplications that are supported by the power supply that triggered anegative determination at step 407. An application may be a thread, aprocess, a virtual machine, or other stream of computer instructionsthat is routinely executed on a processor.

Provided the DCEM server makes a negative determination in step 411, theDCEM server may migrate workloads of a data processing system thatdepend on the affected PSU to another data processing system that doesnot depend on the affected PSU (step 413). A workload is a runningprocess or application of a data processing system. Accordingly, such anapplication or applications that are dependent on the affected powersupply can be migrated to a data processing system not dependent on thepower supply.

Next, or following a positive determination at step 411, the DCEM servermay continue to step 430, explained below.

A negative determination at step 407 can result in the DCEM serverdetermining whether the PSE of the power supply is less than thecorresponding warning level (step 419). Step 419 can involve the DCEMserver looking up the appropriate warning level from a matrix based ontemperature and loading of the power supply. Steps 407 and 419 can beused to determine, on a scheduled basis, that a real-time powerefficiency level is below a corresponding power supply efficiencythreshold. The scheduled basis is a period or time set based on delaysor periods set in, for example, step 437, explained further below.

In response to a positive determination, the DCEM server may make ananomaly report (step 422). An anomaly report can be a warning message oran alarm message. A message can be a message transmitted from themachine. The message can be asynchronously transmitted, or it may besent in response to a user query, for example, as when reviewing a logrendered in HTML.

Further actions may be taken in response to the DCEM determining the PSEvalue is outside of a range. For example, the DCEM may issue amaintenance or inspection request (step 423). Steps 409 and 423 caninvolve the DCEM server transmitting an email to a designated entity,such as a technician, or a vendor to indicate a required remedy as wellas describe the affected PSU. The emails can include, for example, a)maintenance text in the language of the entity; or b) a purchase orderin the language of the entity in the case of step 409. Similarly, theemail can include, for example, a) language concerning maintenance, orb) inspection, in the case of step 423. Further details can be given,such as, for example, the address of the data center, the age andhistory of the affected power supply, as well as any other informationdeemed useful to service the power supply. Alternatively, the DCEM canreport an anomaly report, such as an alarm message or a warning message.

Next, the DCEM server may add the PSU to a low efficiency PSU list (step425). A low efficiency PSU list is a list that includes power suppliesthat are operating below warning level PSEs for some temperature and/orloading configurations of the power supply. The list can be stored todisk in a data structure that can be reviewed by service personnel andupdated in response to service calls. The low PSU list, or lowefficiency PSU list, is a subset of all PSUs that are to be monitored ona more frequent basis than the PSUs generally. Accordingly, iterationsthrough steps of monitoring process 400 may occur on a short delay withrespect to a PSU in the low PSU list, while a long delay may apply tothe period between monitoring (executing step 405) the group of allPSUs.

Accordingly, a next step can be that the DCEM server associates the lowPSU list, and in particular, the PSU that triggers the warning level, toa short delay.

Next, the DCEM server may determine whether it has finished iteratingover PSUs (step 430). Step 430 may be executed in response to a negativedetermination at steps 411 or 419. Step 430 is performed with respect tothe group of PSUs that are to be monitored together. In other words, thegroup can be either the low PSU list, or the entire group of PSUs at thedata center. If further PSUs remain to monitor, a negative branch ofstep 430 is performed, and processing resumes at step 405 for thebalance of the PSUs in the group.

However, a positive determination at step 430 can trigger activityreportable to a user or administrator of the data center. Accordingly,the DCEM server may cause the DCEM server to calculate a DCPCE (step431). The DCPCE can be a ratio of total AC power to total DC power. Sucha report may be made by displaying the DCPCE to a dashboard (step 433).FIG. 5, below, illustrates an example of a dashboard. Since the statusof power supplies is to be monitored routinely, but more frequently forthose that are in the low PSU list, process 400 is re-executed dependingon the time elapsed for either the group of PSUs in the low PSU list, orfor all PSUs. Accordingly, the DCEM server repeats collecting powersupply efficiencies using distinct groups, namely, a low PSU list groupand a group of all PSUs (step 437). As such, the low PSU list is delayedwith a short delay before monitoring step 405 resumes iterating. Incontrast, the entire group of PSUs is iterated based on a long delay,relative to the low PSU list. As can be appreciated, displaying the datacenter power conversion efficiency to a dashboard can include respondingto an HTTP request of an authorized client, and rending the dashboard ina responsive HTTP response to the request.

The DCEM server totals DC power and a totals AC power, using the totalAC power of the data center and replacing a previous input AC power ofthe power supply with a real-time input AC power of the power supply.Similarly, the DCEM server may use the total DC power of the data centerand replace a previous or recent DC power of the power supply with areal-time DC power of the power supplies outputs. A real-time inputalternating power of the power supply is the most recently measured ACpower. Such a real-time input alternating power may be measured and/orcalculated at step 405, above. A real-time DC power of the power supplyis the most recently measured DC power measured from all outputs of thepower supply. These real-time values may be either instantaneous oraverage current and voltage values measured over a sampling period.

Accordingly, the power supply efficiency may calculated using the totalaverage value of measured input AC power and the average value ofmeasured output DC power, over an arbitrary period of time.

Next, the DCEM server may report a ratio of total AC power to total DCpower as DCPCE. Such a report may be made by displaying the DCPCE to adashboard (step 433). FIG. 5, below, illustrates an example of adashboard. Next, the DCEM server may wait an extended time beforerechecking power supplies to get power supply efficiencies for the nextiteration after an arbitrary period of time. The extended time can be aduration on the order of an hour or more. After repeatedly collectingPSE thresholds using distinct groups, low PSU lists, and all powersupplies, with short delays and long delays, respectively, betweenrepeats of each group (step 437), the DCEM server may resume obtainingPSE thresholds and input powers at step 405.

In relation to FIG. 2A, a power supply unit may respond to the steps inthe flowchart of monitoring process 400, when, for example, those stepsare performed by the DCEM server. Such a PSU may rely on an EMS toreceive and store power supply efficiency thresholds on a factoryassembly line, that is, based on the manufacturer's values. The EMS may,once installed to a data center, receive a query for a PSE thresholdfrom the DCEM server, for example, responsive to step 405. Furtherresponsive to step 405, the EMS of the power supply unit may transmitthe PSE thresholds to the DCEM server.

Further processing at the power supply unit may include receiving aquery for real-time PSE, from, for example, the DCEM server. Similarly,in response to such a query, the PSU may transmit the real-time PSElevel. The power supply may be repeatedly queried and provide repeatedresponses, driven by interaction with the DCEM server performing processof monitoring process 400. A query for a PSE threshold may be a packetreceived to a communication unit of the PSU, where the packet has apreset code recognized at the PSU as a request for PSE thresholds.Similarly, the query for a real-time PSE level, can be a packet with acode preset, by convention, to a code that is registered at the PSU toindicate a request for the real-time PSE level. In each query, thepacket may include an IP address or other unique address correspondingto the PSU. Such a packet can also have an IP address that correspondsto the source for the packet. The source can be, for example, the DCEMserver.

FIG. 5 is a dashboard to present a data center power conversionefficiency in accordance with an illustrative embodiment of theinvention. Dashboard 500 may include a report 513, which shows, forexample, by way of a meter, a current data center power conversionefficiency measured for the data center. In particular, dashboard 500may show the data center power conversion efficiency target 509.

In another embodiment, the dashboard can show history of DCPCE valuesover previous sampling times. The dashboard can also show PSU efficiencyof groups of power supplies. Power supplies may be grouped based on PSUmanufacturer, load value, IT equipment class, etc. The dashboard canhave pointers to low efficiency PSU list, high efficiency list, etc.Another alternative is to group PSUs according to the owning line ofbusiness, PSU age, and PSU load value.

FIG. 6 is a flowchart of a PSU embodiment in accordance with anillustrative embodiment of the invention. The PSU may have an embeddedEMS operating according to PSU 210 in FIG. 2A, above. The PSU mayreceive inputs and queries from a DCEM, and correspondingly reportalarms, warnings and other anomalies to a DCEM, either directly orindirectly. Initially, the PSU may measure power related metrics (step601). This step can involve measuring I_(in), I_(out), V_(out) andV_(in) to form measured I_(out), V_(in) and V_(out). I_(in) and may beexpressed as a root mean square (RMS) value for the oscillating current.Next, the PSU may transmit measured power related metrics to a seconddevice (step 603). The second device can be, for example, a DCEM.Furthermore, the transmission of such information may be in response toreceiving a query from the second device.

Next, the PSU may lookup thresholds based on at least one of the powerrelated metrics (step 605). As explained above, especially FIG. 3B, thelooking-up can be additionally based on temperature and loading of thePSU. Next, the PSU may determine if the measured power related metricshave passed a threshold (step 607). This determination can be adetermination that the compared value is above, below, or betweenthresholds. The threshold can be a power supply efficiency threshold ora threshold that is related to the power supply efficiency.

Next, provided a positive result occurs at step 607, the PSU maytransmit an anomaly report (step 609). An anomaly report can be awarning or an alarm. A negative determination can cause the PSU torepeatedly execute step 607. Following each report, the PSU mayrepeatedly test the thresholds be re-executing step 607.

FIG. 7 is a flowchart of a PSU embodiment in accordance with analternative illustrative embodiment of the invention. The PSU may havean embedded EMS operating according to the configuration described inFIG. 2A, above. The PSU may receive inputs and queries from a DCEM, andcorrespondingly report alarms, warnings and other anomalies to a DCEM,either directly or indirectly.

Initially, the PSU may measure power related metrics to form measuredpower related metrics (step 701). This step can involve measuringI_(in), I_(out), V_(out) and V_(in) to form measured I_(in), I_(out),V_(in) and V_(out). These measurements may be performed periodically orduring a self test period. A self test period is the initial period ofoperating a PSU, in which a variable load is applied to each of the PSUoutput pins to test the PSU efficiency under different loadingconditions. Actual production data can be developed from the PSU to filla built-in table with, for example, values for the tables in FIG. 3B.Measurements may be sampled over time and averaged for combinations oftemperature and loading. This step can be carried out by the PSUiterating over a range of temperatures and then over a range of loads,sampling at each stage the power supply efficiency of the PSU, asdescribed above. Accordingly, once sampling is completed, the PSU maycalculate thresholds during the self test period (step 703). Thecalculation can include averaging the values sampled during a self testperiod. Furthermore, having established nominal operating efficiencies,the PSU may set-off from such calculated averages, margins. Thesemargins can be applied to the alarm threshold and warning threshold, forexample, 80% nominal power supply efficiency, and 90% nominal powerefficiency, respectively, for each determined average. In other words,the thresholds are set such that the initial PSEs for a PSU are wellabove the warning threshold and alarm threshold.

Next, the PSU may store the thresholds to the built-in table (step 705).A built-in table is the memory and data stored therein based onestablished thresholds for reporting anomalies, such as, warnings andalarms. At this point, the PSU may be monitored in a mode where actualwarnings or alarms can be detected and reported. Accordingly, the PSUmay measure real-time power related metrics (step 709). Among thereal-time power related metrics, the PSU may measure a real-time I_(in).Real-time I_(in) is a current or sum of currents input to the PSU thatis sampled routinely at intervals short enough to permit monitoring mostdegradation in power supply efficiency performance. Similarly, areal-time value for each power related metric, such as, I_(out), V_(out)and V_(in) is the sampled measurement of each of these quantities forthe entire PSU.

Next, the PSU may transmit the I_(in) and other real-time values aspower related metrics to a second device (step 711). Then, the PSU maycalculate real-time power supply efficiency to form real-time powersupply efficiency based on these values (step 713). Next, the PSU maylookup power supply efficiency thresholds based on at least one ofreal-time power related metrics (step 715). The power supply efficiencythresholds can be looked up based on, for example, real-time I_(in).Alternatively, the power supply efficiency threshold can be looked upbased on, for example I_(out) and V_(out).

Subsequently, the PSU may determine if the measured power supplyefficiency is out of range (step 717). If the measured power supplyefficiency is out of range the PSU may report an anomaly (step 719). Theanomaly report can be a warning sent to a second device.

Some embodiments may hold the anomaly reports or transmittals ofreal-time values in steps 711 and/or 719 until a request or query of thePSU is made by a second device. Accordingly, prior to step 719, the PSUmay receive a query for real-time power supply efficiency. A query forreal-time power supply efficiency is a request made to the PSU by a DCEMor an intermediary device. The query for real-time power supplyefficiency can be made using a networking protocol, including those thatinvolve placing a carrier on conductors that also supply DC power.Responsive to such a query, the PSU may report the real-time powersupply efficiency to the source for the query.

FIG. 8 is a flowchart of an alternative process to transmit anomaliesconcerning power related metrics in accordance with an illustrativeembodiment of the invention. Initially, a PSU may measure a root meansquared (RMS) value for at least I_(in) and V_(in) as well as V_(out)for each output and I_(out) for each output (step 801). Next the PSU maydetermine a phase angle for I_(in) and V_(in) (step 803). The phaseangle can be determined by detecting the zero crossing for the I_(in),the zero crossing for V_(in) and measuring the phase angle between suchzero crossings. In other words, phase angle, φ=Δ×2Π×Freq, where Δ is thedifference between the zero crossings time of the V_(in) as compared toI_(in), and Freq is the frequency of the AC signals V_(in) and I_(in),usually 60 Hz or 50 Hz.

Next, the PSU may lookup the applicable thresholds for each of I_(in),I_(out1) through I_(outn) (where n is the number of outputs), V_(in),V_(out1) through V_(outn), and phase angle of the input voltage andcurrent (step 805).

The PSU may determine whether the I_(in) is greater than a threshold forI_(in), I_(in) _(—) _(max) (step 807). A positive determination mayresult in the PSU transmitting an input over-current anomaly (step 809).The input over-current anomaly is a signal that may identify theaffected PSU and use a pre-determined constant to signal that anover-current has occurred at the PSU.

Next, responsive to a negative determination at step 807 the PSU maydetermine whether the V_(in) is greater than a voltage input threshold,V_(in) _(—) _(max) (step 817). A positive determination may cause thePSU to transmit an input over voltage anomaly (step 819).

Next, responsive to a negative determination at step 817, the PSU maydetermine if V_(in) is less than a minimum input voltage threshold,V_(in) _(—) _(mm) (step 827). A positive determination at step 827 maycause the PSU to transmit an input under voltage anomaly (step 829).

Next, responsive to a negative determination at step 827, the PSU maydetermine whether I_(out) is greater than a maximum threshold, I_(out)_(—) _(max) (step 837). A positive determination may cause the PSU totransmit an output over current anomaly (step 839). Following steps 809,819, 829, 839, the PSU may shut itself down (step 851).

However, a negative determination at step 837 may cause the PSU todetermine whether the phase angle exceeds a maximum phase angle, Φ_(max)(step 847). A positive determination may cause the PSU to transmit a lowpower factor anomaly (step 849).

After a negative determination to step 847 and after step 849, the PSUmay transmit a PSU test success report (step 853). Thereafter, the PSUmay repeat step 801 and subsequent steps for different values of thevariable load.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

The invention can take the form of an entirely hardware embodiment, anentirely software embodiment or an embodiment containing both hardwareand software elements. In a preferred embodiment, the invention isimplemented in software, which includes but is not limited to firmware,resident software, microcode, etc.

Furthermore, the invention can take the form of a computer programproduct accessible from a computer-usable or computer-readable storagedevice providing program code for use by or in connection with acomputer or any instruction execution system. For the purposes of thisdescription, a computer-usable or computer readable storage device canbe any tangible apparatus that can store the program for use by or inconnection with the instruction execution system, apparatus, or device.

The computer-readable storage device can be an electronic, magnetic,optical, electromagnetic, or semiconductor system (or apparatus ordevice). Examples of a computer-readable storage device include asemiconductor or solid state memory, magnetic tape, a removable computerdiskette, a random access memory (RAM), a read-only memory (ROM), or arigid magnetic disk and an optical disk. Current examples of opticaldisks include compact disk—read only memory (CD-ROM), compactdisk—read/write (CD-R/W) and DVD.

A data processing system suitable for storing and/or executing programcode will include at least one processor or a microcontroller coupleddirectly or indirectly to memory elements through a system bus. Thememory elements can include local memory employed during actualexecution of the program code, bulk storage, and cache memories, whichprovide temporary storage of at least some program code in order toreduce the number of times code must be retrieved from bulk storageduring execution.

Input/output or I/O devices (including but not limited to keyboards,displays, pointing devices, etc.) can be coupled to the system eitherdirectly or through intervening I/O controllers.

Network adapters may also be coupled to the system to enable the dataprocessing system to become coupled to other data processing systems orremote printers or storage devices through intervening private or publicnetworks. Modems, cable modem and Ethernet cards are just a few of thecurrently available types of network adapters.

The description of the present invention has been presented for purposesof illustration and description, and is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the art. Theembodiment was chosen and described in order to best explain theprinciples of the invention, the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A computer implemented method for reporting powerconversion efficiency information, the method comprising: receiving, bya computer, a query for real-time power supply efficiency; andresponsive to receiving the query, reporting the real-time power supplyefficiency to a source for the query, wherein the query for real-timepower supply efficiency is a query for the real-time power supplyefficiency for a plurality of power supplies; and increasing powerefficiency among a plurality of power supply units of a data center inresponse reporting the real-time power supply efficiency to the sourcefor the query.
 2. The computer implemented method of claim 1, furthercomprising: querying, by information technology equipment, each powersupply unit for at least one selected from the group consisting of inputcurrent, input voltage, output current, output voltage; and calculating,by information technology equipment, for each power supply the powersupply efficiency.
 3. The computer implemented method of claim 1,further comprising: measuring, by information technology equipment, eachpower supply unit for at least one selected from the group consisting ofinput current, input voltage, output current, output voltage; andcalculating, by information technology equipment, for each power supplythe power supply efficiency.
 4. The computer implemented method of claim1, further comprising: receiving alternating current at inputs; anddistributing alternating current to a plurality of power supplies. 5.The computer implemented method of claim 1, further comprising:receiving direct current at an input; and providing an informationtechnology function.
 6. The computer implemented method of claim 5,further comprising: reporting the real-time power supply efficiency,reporting, by a data center energy management server, a ratio of totalalternating current (AC) power to total direct current (DC) power asdata center power conversion efficiency, wherein the ratio of total ACpower to total DC power is based on information from a plurality ofpower supply units.
 7. The computer implemented method of claim 4,further comprising: querying each power supply of the plurality of powersupplies for at least one selected from the group consisting of inputcurrent, input voltage, output current, output voltage; and calculatingfor each power supply the power supply efficiency.
 8. The computerimplemented method of claim 4, further comprising: measuring each powersupply unit for at least one selected from the group consisting of inputcurrent, input voltage, output current, output voltage; and calculatingfor each power supply the power supply efficiency.